U.S. patent application number 11/797630 was filed with the patent office on 2007-11-15 for solution discharging method and solution discharging device.
This patent application is currently assigned to FUJITSU LIMITED. Invention is credited to Jun Sasaki, Kiyoshi Taninaka, Akihiko Yabuki.
Application Number | 20070264162 11/797630 |
Document ID | / |
Family ID | 38235404 |
Filed Date | 2007-11-15 |
United States Patent
Application |
20070264162 |
Kind Code |
A1 |
Taninaka; Kiyoshi ; et
al. |
November 15, 2007 |
Solution discharging method and solution discharging device
Abstract
A microinjection device includes a pressure-pump and a regulator
that is connected to the pressure pump and that maintains constant
pressure. A regulating chamber is connected to the regulator and an
internal pressure of the regulating chamber is maintained to a
predetermined pressure. A valve is connected to the regulating
chamber and a hollow capillary is connected to the valve. An
operator opens/closes the valve in the process of injecting
material in a cell.
Inventors: |
Taninaka; Kiyoshi;
(Kawasaki, JP) ; Sasaki; Jun; (Kawasaki, JP)
; Yabuki; Akihiko; (Kawasaki, JP) |
Correspondence
Address: |
STAAS & HALSEY LLP
SUITE 700, 1201 NEW YORK AVENUE, N.W.
WASHINGTON
DC
20005
US
|
Assignee: |
FUJITSU LIMITED
Kawasaki
JP
|
Family ID: |
38235404 |
Appl. No.: |
11/797630 |
Filed: |
May 4, 2007 |
Current U.S.
Class: |
422/400 ;
422/62 |
Current CPC
Class: |
G01N 35/1016 20130101;
C12M 35/00 20130101; Y10T 137/218 20150401; C12N 15/89 20130101;
C12M 41/12 20130101; G01N 35/1095 20130101; Y10T 137/2218
20150401 |
Class at
Publication: |
422/100 ;
422/62 |
International
Class: |
B01L 3/02 20060101
B01L003/02 |
Foreign Application Data
Date |
Code |
Application Number |
May 12, 2006 |
JP |
2006-133512 |
Claims
1. A solution discharging method for discharging a solution, from a
hollow capillary with a narrow tip that is filled with the
solution, into a cell due to an action of air pressure, the
solution discharging method comprising: connecting a regulating
chamber to the capillary by a valve; and regulating air in the
regulating chamber at a predetermined pressure before opening and
closing the valve so that regulated pressure has a rectangular
waveform thereby controlling quantity of the solution that is to be
injected from the capillary into the cell to be constant.
2. The solution discharging method according to claim 1, wherein an
integration value of pressure applied to the capillary and time for
which the pressure is applied is controlled to a predetermined
value thereby controlling the quantity of the solution that is to
be injected into the cell.
3. A microinjection device comprising: a pressure pump; a regulator
that is connected to the pressure pump and that maintains constant
pressure; a regulating chamber that is connected to the regulator
and an internal pressure of which is maintained to a predetermined
pressure; a valve that is connected to the regulating chamber; and
a capillary that is connected to the valve and that is used to
inject solution in a cell.
4. The microinjection device according to claim 3, wherein after
the valve is opened, the internal pressure of the regulating
chamber is regulated to a lower pressure than a reverse flow
preventing pressure by closing the valve while the solution is
being injected into the cell.
5. The microinjection device according to claim 3, further
comprising a second valve that is located between the regulator and
the regulating chamber.
6. The microinjection device according to claim 3, wherein the
regulator includes a double system of regulators to maintain a
predetermined pressure that is to be applied to the capillary.
7. The microinjection device according to claim 3, wherein the
regulator includes a double system of regulators to maintain
constant pressure, and the regulating chamber includes a double
system of regulating chambers to maintain the internal pressure to
a predetermined pressure.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention generally relates to injecting
material in the cells by using air pressure.
[0003] 2. Description of the Related Art
[0004] In the field of new drug designing, a microinjection device
is used for injecting a solution (usually a medicinal solution)
into a cell. FIG. 6 is an example of a conventional device. As
shown in the diagram, reference numeral 1 denotes a positive
pressure pump, and reference numeral 2 denotes a negative pressure
pump. Reference numeral 3 denotes a regulator that is connected to
the positive pressure pump 1 and the negative pressure pump 2 for
keeping constant the internal pressures thereof.
[0005] Reference numeral 4 denotes a capillary that discharges a
solution into a cell due to the pressure from the regulator 3. The
capillary 4 is similar to an injection syringe, and has a fine
needle at its tip. The internal diameter of the tip is 0.5 .mu.m
and the external diameter is 1 .mu.m. Reference numeral 6 denotes a
tube that transmits the pressure from the regulator 3 to the
capillary 4, and reference numeral 5 denotes a pressure sensor
which is located in the middle of the tube 6.
[0006] The pressure detected by the pressure sensor 5 is output to
the regulator 3, and the regulator 3 adjusts the internal pressure
so that the pressure detected by the pressure sensor 5 is
maintained constant. Otherwise, it is possible to arrange the
pressure sensor inside the regulator 3 and adjust the internal
pressure so as to maintain constant output from the pressure
sensor. Electric voltage is input to the regulator 3 as a control
signal, and the regulator 3 generates a pressure that is
proportional to the input electric voltage.
[0007] The needle attached to the tip of the capillary 4 is filled
with the solution. Pressure applied by the regulator 3 thrusts a
cylinder of the capillary 4 whereby the solution is discharged
(injected) into the cell. The cell is observed for a change that
occurs after injection of the solution. When the pressure inside
the regulator 3 is to be brought back to the atmospheric pressure,
air is pulled out from the regulator 3 by the negative pressure
pump 2 whereby the pressure inside the regulator 3 is quickly
brought back to the atmospheric pressure.
[0008] FIG. 7 depicts a pressure response curve of the conventional
device. A horizontal axis indicates time and a vertical axis
indicates pressure. Initially, the pressure is maintained to
reverse flow preventing pressure. After time T1 is elapsed, the
pressure reaches up to an injection pressure, and the capillary 4
injects the solution into the cell. The state that the capillary 4
is injected into the cell continues for a predetermined period
after which the pressure lowers gradually. The injecting operation
stops when the pressure reaches the reverse flow preventing
pressure.
[0009] The conventional device can be used in a gene delivery
device. In the gene delivery device, cells that flow through a
micro fluid channel are observed by using a cell observing device,
cells are trapped one by one with a cell trapping device, and
genetic material and medicinal solutions are discharged into the
cells by using a gene delivering micro needle (for example, see
Japanese Patent Application Laid-Open No. 2004-166653).
Furthermore, a microinjection apparatus has, at its tip, a micro
instrument that is connected to a micro syringe, which is filled
with the solution. When a male screw is rotated to move a plunger,
into the micro syringe, the solution is discharged from the micro
instrument (for example, see Japanese Patent Application Laid-Open
No. H03-119989).
[0010] A microinjecting method of the microinjection apparatus
involves filling predetermined volume of a solution in an extra
fine capillary, with a tip that is of .mu.m order, injecting the
solution into the cell by pressurizing the capillary, and observing
the response. In this process, it is necessary to control
sequentially switching of the pressure between a pressure necessary
for discharging the solution in the cell and a pressure necessary
for preventing reverse flow of the solution into the capillary.
[0011] However, the conventional microinjection device, which has
the structure shown in FIG. 6, does not take into account the
pressure transient response. Therefore, when trace quantity of
solution of pl (picolitre) order is to be discharged through
injections such as injections into animal cells, if the delivery
time is lowered to less than 1 second for speeding a discharge
cycle, the set pressure and the set time deviate from the actual
response, and adjustment of discharging volume of the solution is
difficult.
[0012] Therefore, on the conventional microinjection apparatus, an
experienced operator would adjust the pressure and the time for
applying the pressure while taking into account swelling of the
cell when injecting the solution into the cell. However, in this
method, it is unclear whether a constant amount of material is
discharged into the cell.
SUMMARY OF THE INVENTION
[0013] It is an object of the present invention to at least
partially solve the problems in the conventional technology.
[0014] According to an aspect of the present invention, a solution
discharging method for discharging a solution, from a hollow
capillary with a narrow tip that is filled with the solution, into
a cell due to an action of air pressure, includes connecting a
regulating chamber to the capillary by a valve; and regulating air
in the regulating chamber at a predetermined pressure before
opening and closing the valve so that regulated pressure has a
rectangular waveform thereby controlling quantity of the solution
that is to be injected from the capillary into the cell to be
constant.
[0015] According to another aspect of the present invention, a
microinjection device includes a pressure pump; a regulator that is
connected to the pressure pump and that maintains constant
pressure; a regulating chamber that is connected to the regulator
and an internal pressure of which is maintained to a predetermined
pressure; a valve that is connected to the regulating chamber; and
a capillary that is connected to the valve and that is used to
inject solution in a cell.
[0016] The above and other objects, features, advantages and
technical and industrial significance of this invention will be
better understood by reading the following detailed description of
presently preferred embodiments of the invention, when considered
in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a schematic of a first embodiment according to the
present invention;
[0018] FIG. 2 is a graph for explaining a pressure response
according to the present invention;
[0019] FIG. 3 is a schematic of a second embodiment according to
the present invention;
[0020] FIG. 4 is a schematic of a third embodiment according to the
present invention;
[0021] FIG. 5 is a schematic of a fourth embodiment according to
the present invention;
[0022] FIG. 6 is a schematic of an example of the structure of a
conventional device; and
[0023] FIG. 7 is a graph for explaining a pressure response of the
conventional device.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] Exemplary embodiments of the present invention are explained
below in detail with reference to the accompanying drawings. FIG. 1
is a schematic of a first embodiment of the present invention.
Components that are same as those shown in FIG. 6 are indicated
with the same reference numerals. As shown in the diagram,
reference numeral 1 denotes a positive pressure pump, and reference
numeral 2 denotes a negative pressure pump. Reference numeral 3
denotes a regulator that regulates the pressure, reference numeral
10 denotes a regulating chamber that contains air whose pressure is
regulated by the regulator 3. Reference numeral 5 denotes a second
pressure sensor that detects pressure in the regulating chamber 10.
The output of the second pressure sensor 5 is input in the
regulator 3.
[0025] Pressure of air in the regulating chamber 10 is P.sub.2 and
volume is V.sub.2. Reference numeral 4 denotes a capillary that
injects solution into an animal cell and the like, reference
numeral 11 denotes a valve arranged in between the regulating
chamber 10 and the capillary 4. The valve 11, in which the material
used is for example solenoid, is opened and closed to transmit air
from the regulating chamber 10 to the capillary 4. Reference
numeral 12 denotes a pressure sensor 1 that detects pressure of air
in the capillary 4. The pressure of air inside the capillary 4 is
P.sub.1, and the volume is V.sub.1. Operation of the apparatus,
which has such configuration, is explained below.
[0026] At first, pressure of the regulating chamber 10 is set by
the regulator 3 to a certain degree higher than the injection
pressure. When an operator, while watching under a microscope,
confirms that a needle of the capillary 4 reaches the cell, the
operator opens the valve 11 to bring the pressure to injection
pressure level. When the pressure reaches to the injection pressure
level, the valve 11 is immediately closed. While the capillary 4 is
discharging (injecting) the solution into the cell, the regulator 3
adjusts pressure in the regulating chamber 10 and sets it to lower
level of than the reverse flow preventing pressure.
[0027] Afterwards, when the valve 11 is opened, pressure in the
regulating chamber 10 and the capillary 4 becomes equal to the
reverse flow preventing pressure, which prevents the solution from
reverting into the capillary 4. The regulating chamber 10 is set to
lower than the reverse flow preventing pressure in advance, which
makes it possible to bring the level of the pressure entirely to
the reverse flow preventing pressure, when the valve 11 is
opened.
[0028] The relationship between the pressure before the opening of
the valve and the pressure after the opening of the valve can be
obtained through an equation of state of air. When P denotes
pressure after the opening of the valve, P.sub.1 denotes pressure
in the capillary before the opening of the valve, P.sub.2 denotes
pressure in the regulator before the opening of the valve, V.sub.1
denotes volume of air in the capillary, and V.sub.2 denotes volume
of air in the regulator, the pressure P after opening of the valve
and volume ratio .eta.(=V.sub.1/V.sub.2) are represented with
following equations:
P=(.eta.P.sub.1+P.sub.2)/(.eta.+1)) (1)
.eta.=V.sub.1/V.sub.2=(P-P.sub.2)/(P.sub.1-P) (2)
With the help of Equation 1, the pressure P.sub.2 of the regulator
before opening of the valve is represented with the following
equation:
P.sub.2=(.eta.+1)P-.eta.P.sub.1 (3)
.eta. can be calculated from Equation 2. Moreover, the pressure P
after the opening of the valve is set in advance, the pressure
P.sub.1 in the capillary before the opening of the valve is known
in advance from an output from the pressure sensor 12; therefore,
it is possible to calculate the pressure P.sub.2 of the regulator
before the opening of the valve through Equation (3). When the
pressure P.sub.2 of the regulator before the opening of the valve
is set to the value derived through Equation (3), the pressure at
the time of opening of the valve 11 is regulated to the pressure P.
That is, it is possible to maintain the pressure in the regulating
chamber and the capillary.
[0029] Pressure response in an ordinary microinjection device is as
shown in FIG. 7. On the other hand, when the valve is switched from
one state to another state in an instant, the pressure is
transmitted at a sonic speed. The pressure response in such a case
is as shown in a graph in FIG. 2. FIG. 2 is a graph for explaining
the pressure response according to the present invention. The
horizontal axis is time and the vertical axis is the pressure.
[0030] When the valve 11 is opened, the pressure rises from the
reverse flow preventing pressure up to the injection pressure.
Subsequently, when the valve 11 is closed, as shown in the diagram,
the pressure drops to the reverse flow preventing pressure from the
injection pressure in an instant. Rise and fall of the pressure is
faster than the characteristic of the conventional device in FIG.
7.
[0031] As shown in the diagram, although some degree of transient
response occurs due to reflection, time interval required for
responding to regulation of the pressure to the injection pressure
level is still shorter than the response as shown in FIG. 7. As
shown FIG. 7 in the characteristic of the conventional device, the
time required to attain target value is longer, whereas the
transient response of the device in the present invention is only
represented by vibrations near the target value. If the integration
value of the vibrations is considered zero, it can be thought that
the total quantity of injecting solution is proportional to a
product of the target pressure and the time required for
application of the pressure.
[0032] Thus, according to the first embodiment, a valve is arranged
in between a regulating chamber and a capillary, and opened and
closed to control the discharging quantity of solution from the
capillary into a cell. That is, when the solution is injected into
a cell, the quantity of solution can be easily controlled, and
stable microinjection can be performed at high speed with less
effect of transient response. According to the first embodiment,
speedy rise of pressure in the capillary produces a rectangular
waveform that depicts high degree of accuracy in time required for
application of the pressure, high speed injection cycle, and
improved accuracy of the quantity of the injecting solution.
[0033] Generally, the quantity of the injecting solution is
proportional to pressure and time for which the pressure is
applied; therefore, even if there is transient response, a method
of controlling the quantity of the injecting solution according to
the pressure time integration also has the same effect on the
accuracy of the quantity of the injecting solution. That is,
according to the present invention, because the integration value
of the pressure applied to the capillary and the time for which the
pressure is applied is controlled to a predetermined value, it is
possible to always control the quantity of the injecting solution
to a constant quantity.
[0034] FIG. 3 is a schematic of a second embodiment according to
the present invention. Components that are same as those in FIG. 1
are indicated with the same reference numerals. The embodiment
includes a second valve 15 in between the regulator 3 and the
regulating chamber 10. Other aspects of the structure are same as
shown in FIG. 1.
[0035] In such a structure when the first valve 11 is opened and
closed, the second valve 15 is kept closed, which prevents pressure
fluctuations from being conveyed to the regulator 3 and prevents
occurrence of fluctuation in pressure.
[0036] FIG. 4 is a schematic of a third embodiment according to the
present invention. Components that are same as those in FIG. 3 are
indicated with the same reference numerals. In the diagram,
reference numeral 25 denotes a second valve, which is connected to
the regulator 3; reference numeral 20 denotes a second regulating
chamber connected to the second valve; and reference numeral 21
denotes a fourth valve that is connected to the second regulating
chamber. Reference numeral 22 denotes a pressure sensor that
detects a pressure Pi in the first regulating chamber, and
reference numeral 23 denotes a pressure sensor that detects a
pressure Pc in the second regulating chamber. Reference numeral 12
denotes a pressure sensor that detects the pressure in the
capillary.
[0037] Reference numeral 15 denotes the first valve, reference
numeral 10 denotes the first regulating chamber connected to the
first valve, and reference numeral 11 denotes a third valve
connected to the first regulating chamber. The first valve and the
second valve are commonly connected to the regulator 3, and the
third valve and the fourth valve are commonly connected to the
capillary 4.
[0038] Thus, according to the third embodiment, there is provided a
double system of the regulator units formed of valves regulators,
and valves. In this structure, while the third valve is closed, and
the capillary 4 is injecting the solution in the cell, there is no
need to regulate the regulating chamber 10. That is, when one
system is operating the capillary 4, another system regulates the
regulating chamber, and when injection operation of the capillary 4
is completed, opening of the fourth valve leads to a faster
regulation after the opening of the valve. Thus, according to the
third embodiment, time required to switch valves from one state to
another is shortened.
[0039] FIG. 5 is a schematic of a fourth embodiment according to
the present invention. Components that are same as those in FIG. 4
are indicated with the same reference numerals. The embodiment
includes a second regulator 30 corresponding to the second
regulation system shown in FIG. 4. The second regulator 30 is
connected to the positive pump 1 and the negative pump 2, and is
independent of a first regulator 3. The second regulator 30 is
connected to the second valve. Remaining structure is the same as
that shown in FIG. 4.
[0040] Such a structure allows the regulator 3 and a regulator 30
to adjust the air pressure in the regulator chamber independently,
which allows the two systems to operate independently, and this
structure operates faster than the one shown in FIG. 4.
[0041] Thus, according to an aspect of the present invention, high
accuracy of time for which pressure is applied can be achieved due
to fast rise in pressure response that creates rectangular
waveform, and it is possible to have faster injection cycle and
improve accuracy in quantity of discharging solution.
[0042] Although the invention has been described with respect to a
specific embodiment for a complete and clear disclosure, the
appended claims are not to be thus limited but are to be construed
as embodying all modifications and alternative constructions that
may occur to one skilled in the art that fairly fall within the
basic teaching herein set forth.
* * * * *